1. 21
Water Pollution

2. Overview of Chapter 21 Types of Water Pollution Water Quality Today
Agricultural, Municipal, Industrial, Groundwater, Water pollution internationally
Improving Water Quality
Laws Controlling Water Pollution

3. Coal Ash Spill in Dan River, VA, NC
Jan 14, ,000 gallons of coal ash into Dan River
Coal ash (fly ash) – solids left over after coal is burned
Can contain toxic and radioactive chemicals, heavy metals
Water used in fossil fuel extraction

4. Types of Water Pollution
Any physical or chemical change in water that adversely affects the health of humans and other organisms
Eight categories of pollutants (many overlaps among categories)
Sewage, disease-causing agents, sediment pollution, inorganic plant and algal nutrients, organic compounds, inorganic chemicals, radioactive substances, and thermal pollution

5. Sewage
The release of wastewater from drains or sewers (often contains disease-causing agents)
Causes 2 serious environmental problems:
Enrichment
Fertilization of a body of water by high levels nitrogen and phosphorus
Increase in Biological Oxygen Demand (BOD)
Amount of oxygen needed by microorganisms to decompose biological wastes
Via cellular respiration
As BOD increases, Dissolve Oxygen (DO) decreases

6. Sewage

7. Sewage - Eutrophication
Oligotrophic
Unenriched, clear water that supports small populations of aquatic organisms

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9. Sewage - Eutrophication
Slow-flowing stream, lake or estuary enriched by inorganic plant and algal nutrients such as phosphorus
Artificial eutrophication – over nourishment of nutrients due to human activities

10. Artificial eutrophication
Sequence of events:
Nutrients (Nitrogen and Phosphorous) added to waterway triggers an algal bloom
Algae go through life cycle and die….sink to bottom
Decomposing bacteria feed upon dead algae and multiply, increasing Biochemical Oxygen demand, and proceed to consume oxygen from the water
Dissolved oxygen levels drop, often to below acceptable standards for fish & other aquatic organisms.

11. Disease-causing Agents
Infectious organisms that cause diseases
Originate in the wastes of infected individuals
Common bacterial or viral diseases:
Typhoid, cholera, bacterial dysentery, polio, and infectious hepatitis

12. Disease-causing Agents

13. Disease-causing Agents
Monitored by testing for presence of E. coli in the water via a fecal coliform test
Indicates the presence of pathogenic organisms

14. Sediment Pollution
Excessive amounts of suspended soil particles eventually settle and accumulate on bottom
Originates from erosion of agricultural lands, forest soils exposed by logging, degraded stream banks, overgrazed rangelands, strip mines, and construction
Problems
Limits light penetration
Covers aquatic animals and plants
Brings insoluble toxins into waterways
Changes available habitat for aquatic organisms

15. Sediment Pollution
7% of sediments in U.S. watersheds seriously contaminated with toxic pollutants
Eating fish from these may threaten human health

17. Inorganic Plant and Algal Nutrients
Nitrogen and phosphorus that stimulate the growth of plants and algae
Harmful in large concentrations
Sources:
Human and animal wastes, plant residues, atmospheric deposition, and fertilizer runoff
Results in:
Enrichment, bad odors, and a high BOD

18. Inorganic Plant and Algal Nutrient- The Dead Zone
Livestock produce 20x feces and urine of humans
Laws do not require waste treatment
High BOD can result in hypoxia
Low O2 zones

19. Inorganic Plant and Algal Nutrient- The Dead Zone

20. Organic Compounds Chemicals that contain carbon and hydrogen atoms
Natural examples: sugars, amino acids, and oils
Human-made examples: pesticides, solvents, industrial chemicals, and plastics

21. Organic compounds Volatile organic compounds (VOCs)
Organic compounds that easily enter the surrounding air, can redeposit
Endocrine disruptors
Organic chemicals that mimic hormones
Chemicals measure in parts per billion (ppb) or parts per millions (ppm)
ppm 1000X larger than ppb
Some chemicals cause problems at very low concentrations

22. Volatile Organic Compounds in Groundwater

23. Inorganic Chemicals
Contaminants that contain elements other than carbon
Acids, salts, heavy metals
Do not degrade easily
Lead
Found in old paint, industrial pollutants, leaded gasoline
Mercury
Mercury bioaccumulates in the muscles of top predators of the open ocean

24. Radioactive Substances
Contain atoms of unstable isotopes that spontaneously emit radiation
Sources
Mining
Processing radioactive materials
Medical and Research Facilities
Nuclear power plants
Natural sources

25. Thermal Pollution
Occurs when heated water produced during industrial processes is released into waterways
Commonly released
Organisms affected
Temperature affects reproductive cycles, digestion rates, and respiration rates
Warm water holds less DO than cold water

26. Two Types of Water Pollution
Point Source Pollution
Water pollution that can be traced to a specific origin
Non-point Source Pollution
Pollutants that enter bodies of water over large areas rather than being concentrated at a single point of entry
Diffuse, but its cumulative effect is very large
Differentiated because one is easier to decrease than other

27. Water Pollution from Agriculture
Agriculture is leading source of water pollution in U.S.
Animal wastes and plants residues have high BOD
Chemical pesticides can leach into groundwater
Almost all streams and rivers are polluted with agricultural pesticides
72% of water pollution in rivers is from agriculture

28. Municipal Water Pollution
Sewage treatment is point source
Urban runoff is nonpoint source
Combined sewer systems
Human and industrial wastes combined before sent to waste water treatment
Infrastructure is old and processing can be backed up
High rainfalls can overflow sewers
Combined sewer overflows into nearby waters without being treated (untreated sewage)

29. Municipal Water Pollution

30. Industrial Wastes in Water
Different industries generate different pollutants
Food processing plants - high BOD
Paper mills - High BOD and toxic compounds
Many industries recover toxins before they go into the waste stream

31. Case-In-Point Green Chemistry- Sources of synthetic pollutants in water
Green chemistry – chemistry designed to reduce or halt use/production of hazardous substances

32. Groundwater Pollution

33. Water Pollution in Other Countries
Lake Maracaibo, Venezuela
10,000 drill platform oil wells tap lake bottom
Leak oil into lake
Agricultural wastes from local fields
Until recently, raw human waste polluted the lake

34. Water Pollution in Other Countries
Po River, Italy
Similar to Mississippi River
Pollutants: Sewage, industrial wastes, sediment
~17 million Italians depend on the river for drinking water
Cleanup will require a national management plan and may take decades

35. Water Pollution in Other Countries
Ganges River, India
Used for bathing and washing clothing
Sewage and industrial waste discharged into river (also p. 429….incompletely burned bodies!)
Ganga Action Plan initiated by government
Construction of 29 sewage treatment plants

36. Water Pollution in Other Countries
Zimbabwe
– cholera outbreak
4000 deaths, 100,000 cases
Uneducated about cause of disease
Bangladesh
Arsenic poisoning from project to increase access to clean water
Project installed hand pumps for groundwater rather than contaminated surface water
Groundwater had high natural concentrations of arsenic (lead to deaths from cancer)

37. Purification of Drinking Water

38. Purification of Drinking Water
In U.S., most municipal water supplies are treated
Collected from water or reservoir
Treated
Treated water distributed to customers
Sewer lines bring sewage to treatment plant
Sewage treated at sewage treatment plant

39. Purification of Drinking Water
Chlorine Dilemma (see P. 430)
Chlorine byproducts are linked to numerous cancers, miscarriages and birth defects
Peru stopped using chlorine
huge cholera epidemic that infected 300,000 people
Fluoridation (see P. 430)
70% of U.S. drinking water is fluoridated
Prevents tooth decay
Once believed to be linked to cancer, kidney disease - current studies do not show this

40. Municipal Sewage Treatment
Primary treatment
Removing suspended and floating particles by mechanical processes
Secondary treatment
Treating wastewater biologically to decompose suspended organic material; reduces BOD

41. Municipal Sewage Treatment

42. Municipal Sewage Treatment
Sewage Sludge
Solids remaining after primary and secondary sewage treatment has been completed
Tertiary treatment
Advanced wastewater treatment methods that are sometimes employed after primary and secondary treatments
Reduce phosphorus and nitrogen

43. Municipal Sewage Treatment

44. Individual Septic System- Septic Tank

45. Individual Septic System- Drain Field

46. Laws Controlling Water Pollution
Citizen Watchdogs to Monitor Pollution
Safe Drinking Water Act (1974) – see p
Set uniform federal standards for drinking water including maximum contaminant levels (MCL’s)
This does not cover private water wells, but does ensure that each state is following EPA MCL’s in public water sources
Amendments in 1996 requires municipal water suppliers to disclose what contaminants are present in their city’s water supply, and what the health risks are
Clean Water Act (1972)
EPA sets up and monitors National Emissions Limitations
Effectively improved water quality from point sources

47. Laws Controlling Water Pollution
Clean Water Act (1972)
2 Basic Goals:
1. Eliminate the discharge of pollutants in U.S. waterways
2. Attain water quality levels that make U.S. waterways safe for fishing and swimming
To achieve goals, EPA sets up and monitors National Emissions Limitations: the maximum possible amount of a water pollutant that can be discharged from a sewage treatment plant, factory, or other point source
Effectively improved water quality from point sources

48. Laws Controlling Water Pollution
Clean Water Act (1972)
Point sources (factories, for example) must obtain permits from the EPA as part of the “National Pollution Discharge Elimination System” = NPDES
1987 amendments expand the clean water act to account for nonpoint sources such as erosion from construction sites…but more must be done to prevent pollution from mining, agriculture, etc.
study indicates that 29% of U.S. rivers, 43% of U.S. lakes and 38% U.S. estuaries are still too polluted for fishing, swimming or drinking!

49. Laws that Protect Groundwater
Safe Drinking Water Act
National Pollutant Discharge Elimination System (NPDES)
Resource, Conservation and Recovery Act